1. Field of the Invention
This invention relates generally to surge brake apparatus for operating the wheel brakes of trailers, and more particularly to a surge brake apparatus for gooseneck trailers.
2. Brief Description of the Prior Art
Surge braking apparatus for trailers are known in the art. There are several patents which disclose various surge brake apparatus for trailers, all of which are directed toward a surge protector mechanism in the tongue portion of the trailer hitch rather than the ball portion of the coupling. None of the prior art patents are particularly suited for use with a gooseneck trailer wherein the surge protector is mounted in the bed of a truck.
Ewald et al, U.S. Pat. No. 3,880,263 discloses a system in the tongue portion of the trailer hitch wherein a resilient coupling is surrounded by telescoping members to activate a brake cylinder. A shock absorber dampens the force transmitted to the brake cylinder. A solenoid mechanism is connected in a bypass line to the cylinder and actuated by the backup lights when the gear shift is placed in reverse gear to bypass feeding the cylinder and conduct the brake fluid into a reservoir so that the trailer can be backed up.
Parkhurst, U.S. Pat. No. 2,969,857 discloses a bracket in the tongue portion of a trailer coupling which contains a master brake cylinder. A spring dampens the force transmitted to the brake cylinder. A solenoid mechanism is connected in a bypass line to the cylinder and actuated by the backup lights when the gear shift is placed in reverse gear to bypass feeding the cylinder and conduct the brake fluid into a reservoir so that the trailer can be backed up. When backing, a latch mechanism locks the moving parts against movement to render the system inoperative.
Machamer, U.S. Pat. No. 2,574,406 discloses a surge device on the tongue portion of a trailer hitch comprising a pair of spring biased telescoping members and a hydraulic cylinder mounted to the tongue and actuated by an elongate rod extending from the ball portion of the hitch.
Fiske, U.S. Pat. No. 2,630,888 discloses a surge device on the tongue portion of a trailer hitch comprising a hydraulic master brake cylinder mounted on a spring biased draw bar which moves relative to the cylinder upon the towing vehicle being slowed down. The relative movement and degree of braking is adjustably controlled by the spring stiffness.
Davids, U.S. Pat. No. 2,834,436 discloses an automatic brake applicator on the tongue portion of a trailer which includes means for cushioning and controlling the amount of brake application applied to the trailer depending upon the weight of the trailer and its load.
Eksergian, U.S. Pat. No. 3,007,552 discloses a surge protector on the tongue portion of a trailer frame which inhibits the intermittent application and release of the trailer brakes due to the uneven forward movement of the trailer caused by road irregularities. The device employs a swinging instead of sliding movement between relatively movable parts.
Krotz, U.S. Pat. No. 3,065,830 discloses an emergency brake mechanism in the tongue portion of a trailer frame which automatically applies the brakes of the trailer in the event it vehicle accidentally becomes disconnected from the towing vehicle.
Wherry, U.S. Pat. No. 3,215,230 discloses a surge device employing two members which move relative to one another and which are connected to the towing vehicle and the trailer respectively. A brake cylinder and shock absorber are mounted on one of the members and connected to a lever pivotally attached to the other member which compresses a spring for actuation of the master cylinder piston rod. The spring is the force upon which operation of the master cylinder is directly dependent, rather than the relative movement of the two members.
Kolm, U.S. Pat. No. 3,796,287 discloses a surge protector in the tongue portion of the hitch for providing a force multiplication whereby an increased fluid pressure output can be obtained particularly for disk brake actuation. The force multiplication apparatus includes a toggle linkage system and a cam that actuates the joint of the toggle linkage. A shock absorber provides a smoother brake operation.
The present invention is distinguished over the prior art in general, and these patents in particular by a surge brake apparatus comprising a base plate adapted to be affixed to the tow vehicle and having a sliding plate which moves relative to the tow vehicle and carries a trailer hitch ball to receive the tongue portion of the wheeled trailer. A hydraulic master cylinder is removably mounted on the base plate stationary relative to the sliding plate and connected by conduit to the hydraulic brakes of the towed trailer. An actuating rod on the sliding plate is operatively connected to the master cylinder piston whereby forward movement of the sliding plate will pressurize the fluid therein to activate the wheel brakes of the trailer as the tow vehicle is slowed down. An electric solenoid is removably mounted on the base plate and operated from the tow vehicle to selectively move a latch between locked and unlocked positions to prevent relative movement between the sliding plate and the master cylinder whereby the trailer may be backed up by the tow vehicle without actuation of the trailer brakes. The master cylinder may be removed from the tow vehicle and stored on the trailer without disconnecting the hydraulic line, and the solenoid may be removed from the base plate and stored on the tow vehicle without disconnecting the electrical conduit when the trailer is not being towed.